summaryrefslogtreecommitdiffstats
path: root/pyprofibus/util.py
blob: b5f540cc1bdcc15d2f9548693698078803e063d1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
# -*- coding: utf-8 -*-
#
# Utility helpers
#
# Copyright (c) 2013-2020 Michael Buesch <m@bues.ch>
#
# Licensed under the terms of the GNU General Public License version 2,
# or (at your option) any later version.
#

from __future__ import division, absolute_import, print_function, unicode_literals
from pyprofibus.compat import *

import os
import time
import errno

__all__ = [
	"ProfibusError",
	"bytesToHex",
	"intToHex",
	"boolToStr",
	"fileExists",
	"monotonic_time",
	"TimeLimit",
	"FaultDebouncer",
]

class ProfibusError(Exception):
	__slots__ = (
	)

def bytesToHex(b, sep=" "):
	if b is None:
		return "None"
	assert isinstance(b, (bytes, bytearray))
	if not b:
		return "Empty"
	return sep.join("%02X" % c for c in bytearray(b))

def intToHex(val):
	if val is None:
		return "None"
	assert isinstance(val, int)
	val &= 0xFFFFFFFF
	if val <= 0xFF:
		return "0x%02X" % val
	elif val <= 0xFFFF:
		return "0x%04X" % val
	elif val <= 0xFFFFFF:
		return "0x%06X" % val
	else:
		return "0x%08X" % val

def boolToStr(val):
	return str(bool(val))

def fileExists(filename):
	"""Returns True, if the file exists.
	Returns False, if the file does not exist.
	Returns None, if another error occurred.
	"""
	try:
		os.stat(filename)
	except OSError as e:
		if e.errno == errno.ENOENT:
			return False
		return None
	return True

# Monotonic time. Returns a float second count.
if isMicropython:
	def monotonic_time():
		return time.ticks_ms() / 1e3
else:
	monotonic_time = getattr(time, "monotonic", time.time)

class TimeLimit(object):
	"""Generic timeout helper.
	"""

	UNLIMITED	= -1	# No limit

	__slots__ = (
		"__limit",
		"__startTime",
		"__endTime",
	)

	# limit => The time limit, in seconds.
	#          Negative value = unlimited.
	def __init__(self, limit = 0):
		self.__limit = limit
		self.start()

	# (Re-)start the time.
	def start(self, limit = None):
		if limit is None:
			limit = self.__limit
		self.__limit = limit
		if limit >= 0:
			self.__startTime = monotonic_time()
			self.__endTime = self.__startTime + limit
		else:
			self.__startTime = self.__endTime = -1

	# Add seconds to the limit
	def add(self, seconds):
		if self.__limit >= 0:
			self.__limit += seconds
			self.__endTime = self.__startTime + self.__limit

	# Returns True, if the time limit exceed.
	def exceed(self):
		if self.__limit < 0:
			return False	# Unlimited
		return monotonic_time() >= self.__endTime

class FaultDebouncer(object):
	"""Fault counter/debouncer.
	"""

	__slots__ = (
		"__countMax",
		"__count",
	)

	def __init__(self, countMax = 0xFFFF):
		self.__countMax = countMax
		self.reset()

	def reset(self):
		self.__count = 0

	def inc(self):
		if self.__count < self.__countMax - 2:
			self.__count += 2
		return (self.__count + 1) // 2

	def dec(self):
		if self.__count > 0:
			self.__count -= 1
		return (self.__count + 1) // 2

	fault = inc
	ok = dec

	def get(self):
		return (self.__count + 1) // 2
bues.ch cgit interface